Yeah from what I read here, Halsins romance seems toxic as hell ( at least hell has good music, as heard in act3). I'm ok with him being poly, but as others said, the way it is represented is not healthy. And I already hated it, how creepy he came at my girl, just because she asked if he had settled in. Otherwise I didn't really talk to him.
I do think, his whole companion status is a bad meme - you want him? Let's make him hot for everything? Companion story? Naah, we don't need that, just make him hit on everyone, that's enough.
You can't even tell him at the end of act 2 to get back to the grove or stay with Thaniel. Every other companion has a line, where you can deny them joining you, even that other fan request Minthara from what I've read. But Halsin is just forced on you.
Tbh it was wrong to give in to fan request to get that. The character is completely destroyed for me and I liked him before - not like others here, he was a pleasant NPC and camp follower with a bit of awkwardness about his leaderskills.
I think, he either needs a complete rewrite or he should be scratched for a better companion. As he is now he just not working out.
When even his superfan Icelyn has something not so good to say, then there is something very wrong.
And I want to clearify: it is not the poly, I have a problem with, representation is good, but him being a sex pest and a really bad written meme character.
I'm planning to just make it so that he will get
abducted by Orin
next time to have him out of my game for a while.

"We are all stories in the end. Just make it a good one."

Doctor Who